1. Field of the Invention
The present invention relates to an image processing technique. More particularly, the present invention relates to an image interpolation processing device and a method thereof.
2. Description of Related Art
FIG. 1 is a schematic diagram illustrating spatial lengths of image patterns under different resolutions. As shown in FIG. 1, spatial (images) lengths of the same pattern segment are different under different resolutions. The larger the resolution is, the larger the sampling length of the system is, so as to obtain the same result as that obtained under the low resolution. For example, a length occupied by a window A with a low resolution at the left side of FIG. 1 has to be enlarged to a length occupied by a window B with a high resolution at the right side of FIG. 1, so as to maintain an intact image; otherwise, in case of the high resolution, if the window A with the original low resolution is still applied, only segment information can be observed under the high resolution, which may cause a distortion of the image.
Moreover, lengths of the same oblique line under different resolutions are different. Therefore, when a fixed pixel pipe is used for temporarily storing or analysing data, it can only be applied to a situation of single resolution. Once data with higher resolutions are required to be analysed, inaccuracy due to incomplete scope will affect the final output image quality. A solution of a conventional technique is to increase the pixel pipe up to a maximum demand for a worst case. The so-called worst case refers to a maximum cost of hardware required for implementing a most complicated result. Namely, as long as there is a little possibility of demand, the required circuit resource then has to be reserved in a physical circuit. However, to implement an algorithm with varied complexity based on such method can cause a huge consumption of hardware cost.
For example, FIG. 2 is a schematic diagram of operation windows required when a conventional deinterlacing operation is performed. As shown in FIG. 2, when the deinterlacing operation is performed to two adjacent lines 10 in an image frame, the conventional method is to perform an analysis based on movement of the so-called operation windows. Different data analysis is performed at different time within the operation windows 1˜3, and sometimes the data before and after analysed might have an inheritance relation. However, the pixel numbers required by the operation window 1 and the operation windows 2 and 3 might be different, and therefore the maximum pixel pipe length is required, i.e., the so-called fixed scope structure. As described above, change of the resolution might change the length of a diagonal edge. Therefore, the length of the hardware structure has to be elongated for obtaining the intact diagonal edge. However, the maximum length of the pixel pipe is not always used in an actual application. Therefore, such method is not quite economic. Moreover, due to the inheritance of the analysed data, it implies a demand of storing intermediate calculated values; namely, the original data and the intermediate analysed values are required to be stored simultaneously for the conventional method, which may lead to a relatively great cost. Accordingly, only a little data can be obtained, and the hardware structure is limited.
In summary, since performing the diagonal edge enhancement to determine a direction has to observe information of neighbouring pixels of indefinite lengths, a pixel pipe buffer with a certain length has to be set for implementing the conventional method. However, as described above, methods of using the pixel pipe restrict the observable width of the operation window due to limitation of the hardware resources. Moreover, the conventional method has excessive dependence on the original data, causing unavoidable increase of hardware and investment, so that the cost thereof is increased. Moreover, for different resolutions, the solution is either to sacrifice a display quality or increase an extra hardware cost.
Therefore, it requires a simple structure without increasing of the hardware cost for the deinterlacing interpolation technique in order to achieve a displaying correctness under the high resolution.